Since the deaths, officials estimate that about 80 to 100 ducks remain at the 3.5-acre lake -- too many birds for a lake of that size. So, with the help of a local animal rights advocate, city officials hope to find someone with a private pond or lake.

"We're looking for a place where the ducks will have an environment that will protect them from being used for medical experiments or being harmed in any way," Gessner said.

Gessner said the round of disease appears to be subsiding, with only one dead duck found yesterday morning.

Some residents transported sick ducks to the Alexander Lindsay Jr. Museum in Walnut Creek, a natural history museum that operates a wildlife rehabilitation center.

Ducks at Ellis Lake have had more than their share of problems, largely due to the lake's murky conditions.

But the city is prepared to spend about $60,000 to improve the lake by installing a well and an aeration system that would oxygenate the water.

"The possibility of having a well to keep the water alive and fresh at all times will certainly help," Gessner said.

The city also has a contract with Contra Costa Landscape Maintenance to monitor water quality at Ellis Lake.